1. Field of the Invention
The present invention relates to a belt to be used particularly in a washing step for removing ink particles and ash content from an aqueous solution of paper materials regenerated as a result of de-inking or de-ashing of wastepaper such as newspaper or a in a step of dehydrating the aqueous solution or thickening pulp raw materials; and a manufacturing method of the belt.
2. Description of the Related Art
A thickening machine is employed in a washing step for removing ink particles and ash content from an aqueous solution of paper materials regenerated by de-inking or de-ashing of wastepaper such as newspaper and magazine or in a step of dewatering and thickening pulp raw materials.
There are some kinds of thickening machines but any of them has a mechanism of reducing the water content of paper materials or pulp raw materials. One of them is a thickening machine equipped with two rolls and an endless belt which is made of a fabric and suspended on these rolls. In this machine, pulp materials are supplied between these rolls and belt and by the nip pressure between the inner roll and belt and centrifugal force caused by high speed rotation, ink particles, ash content, too minute fibers to form paper, and excess water are removed continuously from an aqueous solution of paper materials.
In paper making, materials are supplied onto a belt uniformly in small portions. In thickening of paper materials such as waste paper, on the other hand, a solid content in the unevenly dispersed form is released onto the belt. A large load is therefore applied unevenly to the fabric and the endless belt may be deformed and torn when the rotating belt travels obliquely. In order to prevent such a phenomenon, an attempt has been made to equip a fabric, at an end portion thereof in a width direction, with a guide protrusion and also with a bending-resistant element for preventing breaking of the fabric on the boundary surface between the guide protrusion and fabric.
In Japanese Patent Laid-Open No. H04-361682 (1992), disclosed is a fabric having a guide and a bending-resistant element fusion-bonded thereto. The thickening belt disclosed herein has a conventionally employed structure and a typical guide-attached portion is shown in FIG. 2 of the document. In spite that the guide protrusion is attached to the belt well, the guide performance of the belt is not still sufficient. The guide protrusion inevitably runs on a roll by wild meandering or this causes breaking of the fabric at the boundary between the bending-resistant element and fabric.